1. Field of the Invention
The present invention generally relates to an image forming sheet, an operating apparatus, an image forming apparatus, and an image forming method. More specifically, the present invention is directed to such an image forming sheet, an operating apparatus, an image forming apparatus, and an image forming method, capable of forming an image by applying either an electric filed or a magnetic field to an image forming layer, while no transparent electrode is used.
2. Description of the Related Art
Conventionally, the image forming apparatuses have been proposed in which the image forming sheets are detachably mounted on the drive apparatuses. These image forming sheets can be handled as xe2x80x9cpaperxe2x80x9d (for example, Japanese Laid-open Patent Application Hei. 2-25440 and Japanese Laid-open Patent Application Hei. 4-355786).
This one conventional image forming apparatus, as represented in FIG. 9, is arranged as follows: That is, the liquid crystal panel 50A is detachably mounted on the drive apparatus 60 for selectively applying the voltages to the respective electrodes of this LCD panel 50A. The LCD panel 50A is equipped with the sheet-shape-arranged liquid crystal layer (not shown); a plurality of data electrodes positioned in the vicinity of one surface of this LCD layer, and in which a plurality of electrodes arranged along a preselected direction are arrayed in a preselected pitch (approximately 0.3 [mm]) along a direction perpendicular to the predetermined direction; and furthermore, a plurality of scanning electrodes positioned in the vicinity of the other surface of this LCD layer, and in which a plurality of electrodes arranged along a preselected direction are arrayed in a preselected pitch (approximately 0.3 [mm]) along a direction perpendicular to the predetermined direction.
To externally observe images formed in this conventional image forming apparatus, a high-cost transparent electrode must be employed so as to construct any one of the data electrode layer and the scanning electrode layer.
Also, in order to mount the LCD panel 50 on the drive apparatus 60, the respective electrode lines of the matrix electrode should be electrically Connected to the signal lines for the electrodes of the drive apparatus in a proper manner. However, as previously described, the pitch between the respective electrodes is set to approximately 0.3 [mm]. Under such a circumstance, it is practically difficult to correctly mount the LCD panel 50A on the drive apparatus 60 in order that the respective electrode lines of the matrix electrode are properly connected to the signal lines for the electrodes employed in the drive apparatus. As a result, such an image forming apparatus that the LCD panel 50A is detachably mounted on the drive apparatus 60 in the proper manner could constitute an ideal image forming apparatus. In other words, practically speaking, this image forming apparatus can be hardly realized.
Also, for example, another conventional image forming, apparatus has been described in U.S. Pat. No. 4,143,103 (Applicant: XEROX corporation). As indicated in FIG. 10, in this image forming apparatus, the image forming sheet 5OB is detachably mounted on the drive apparatus (not shown) . This image forming sheet 50B is constituted by the image forming layer 52 for rotatably storing a plurality of 2-color rotating member particles (not shown) into a sheet-shaped elastomer. These 2-color rotating member particles are painted in two colors, and the respective surface charges of these colors are different from each other. This image forming apparatus is further arranged by the data electrode layer 54 arranged on one side of this image forming apparatus 52; the scanning electrode layer 56 arranged on the other side of this image forming apparatus 52; and one pair of boards 59 and 60 for sandwiching these image forming apparatus 52, data electrode layer 54, and the scanning electrode layer 56. It should be understood that in this image forming layer 52 of the image forming apparatus (see FIG. 10), the surface resistances of the visible side surface and another side surface located opposite to this visible side surface are made equal to each other and also made large.
Similarly, in order to externally observe the image, any one of the visible sides of the data electrode layer 54 and the scanning electrode 56 must be made of the expensive transparent electrode layer. Alternatively, the image may be formed without such a transparent electrode layer. In this alternative case, the image forming condition cannot be confirmed. In other words, no confirmation can be made of the image unless the image is written into the image forming sheet 50B, and this image forming sheet 50B is derived from any one of the data electrode layer 54 and the scanning electrode layer 56. This alternative image forming method may simply have the same function as a simple printer. Therefore, this alternative image forming method cannot achieve the merit of the detachable image forming apparatus, namely, the image forming sheet can be handled as paper.
On the other hand, the above-described drawback can be solved by such an image forming technique as disclosed in Japanese Laid-open Patent Application Hei. 6-35370, which is capable of hardly the image forming sheet. This conventional image forming technique is to form the image on the electrophoresis image forming display sheet, while the electrostatic latent image is formed on the photosensitive member and the image is formed based on this electrostatic latent image. The protection plate having the transparent electrode layer is provided on the electrophoresis image display sheet on which the image is formed. In accordance with this prior art technique, the image forming sheet is made flexible, and therefore, this sheet can be handled as paper. However, in general, an easily-broken ITO is used as this transparent electrode. When this ITO image forming sheet is rounded, or roughly handled, this transparent electrode would be broken. Therefore, this transparent electrode must be made flexible. However, none of the conventional image forming techniques describes, or teaches this solution method.
The present invention has been made to solve the above-explained drawbacks, and therefore, has an object to provide an image forming sheet, an operating apparatus, an image forming apparatus equipped with these image forming sheet and operating apparatus, and also, as image forming method, capable of confirming an image without employing a transparent electrode.
To achieve the above-described object, an image forming sheet, according to an aspect of the present invention, is featured by comprising a sheet-shaped image forming layer for forming thereon a visible image by being applied by any one of an electric field and a magnetic field and a pair of flexible films for supporting the image forming layer from both surface sides thereof without having an electrode, one of an electric resistance and a magnetic resistance of one flexible film being smaller than that of the other flexible film.
In this case, the image forming layer forms such a color image in response to the applied direction of the electric field, or the magnetic field. It should be noted that at least one of the paired films is made transparent.
Also, an operating apparatus, according to another aspect of the present invention, is featured by that either the electric field or the magnetic field is applied to the image forming sheet from the other film surface side in order to form the image thereon in response to the image data.
Then, an image forming apparatus, according to another aspect of the present invention, is featured by employing the above-explained image forming sheet and the above-described operating apparatus. It should be noted that the image forming sheet and the operating apparatus are detachably mounted.
Also, to form an image, a sheet-shaped image forming layer for forming a visible image thereon by being applied by one of an electric field and a magnetic field is supported from both side surfaces thereof by one pair of flexible films having no electrode, one of an electric resistance and a magnetic resistance of one flexible film being smaller than that of the other flexible film; and one of the electric field and the magnetic field is applied to both the image forming layer and the one pair of films from the other film side so as to form an image in response to image data.
As previously explained in detail, since the operating apparatus used to form the image may apply either the electric field or the magnetic field to the image forming sheet, the image forming sheet is no longer required to have such a high-cost transparent electrode.
Also, since only the portion within the image forming sheet may constitute the image forming region, to which either the electric field or the magnetic field is applied, the image forming sheet can be very easily mounted on the operating apparatus. In addition, the image forming sheet of the present invention is not so arranged that the image forming layer is sandwiched by the data electrode layer and the scanning electrode layer, but is simply arranged in such a manner that the operating apparatus may apply either the electric field or the magnetic filed to the image forming sheet so as to form the desirable image. This image forming sheet is equipped with one pair of flexible films which do not own the image forming layer and also the electrode capable of supporting this image forming layer from both side surfaces thereof. It should be understood that since one pair of flexible films without having the electrode are employed, there is no line interrupt problem.
On the other hand, each of the above-explained one paired films may contain a first area portion for supporting an overall area of the image forming layer from both aide surfaces thereof; and a second area portion arranged around the first area portion. The image forming sheet is further comprised of: a member having the same characteristic (e.g., same electric capacitance, same magnetic capacitance) as that of the image forming layer, which is arranged between the second area portions of the one pair of films and also is supported by the second area portions.
The operating apparatus may be comprised of a first operating portion for applying one of the electric field and the magnetic field in response to the image data and a second operating portion arranged around the first operating portion and for applying one of the electric filed and the magnetic filed irrespective of the image data.
That is to say, the image forming sheet is arranged on the operating apparatus in such a manner that the first area portion corresponds to the first operating portion, and furthermore, the second area portion corresponds to the second operating portion.
Now, when the operating apparatus is equipped with only the first operating portion, in such a case that the entire first operating portion applies the magnetic field or the electric field having the same strengths so as to form the same colored image over the entire image forming layer, each of one-paired films is charged, or magnetized by the same degree, but either the electric field or the magnetic field can not be applied to the image forming layer. That is, it is not possible to form the same-colored image over the entire area of this image forming layer.
However, as explained above, when the operating apparatus is equipped with the first operating portion and the second operating portion, even when the entire portion of the first operating portion may apply the electric field or the magnetic field having the same degrees, the respective one-paired films are influenced by the electric field or the magnetic field from the second operating portion. As a result, since the first area portion and the second area portion of the other film are charged, or magnetized with different degrees, the same colored image can be formed over the entire image forming layer. The above explanation is also true in the case where a predetermined-colored image is formed on most of the image forming layer and a different color is applied only on small portion of the layer.
In this case, as previously explained, when such a member having the same characteristic (for example, same electric capacitance, or same magnetic capacitance) as that of the image forming layer is arranged between the second area portions of one-paired films located at the position corresponding to the second operating portion, either the electric field or the magnetic field can be readily applied to the image forming layer.
Alternatively, the following image forming sheet may be applied instead of the above-explained image forming sheet. That is, this alternative image forming sheet is featured by comprising: a sheet-shaped image forming layer for forming thereon a visible image by being applied by any one of an electric field and a magnetic field; and sheet-shaped supporting means for supporting the image forming layer from both surface sides thereof, one of an electric resistance and a magnetic resistance of a first viewed surface of the sheet-shaped supporting means being smaller than that of a second viewed surface positioned opposite to the first viewed surface.